You asked

What should baby have for breakfast?

Breakfast is such an important meal of the day for everyone and your baby is no exception. You can use your own breakfast needs as a good template for what you can give your baby.
6 months:
Starting off, you can try puréeing pear, apple, kiwi, or banana. A great idea, which babies seem to love is to purée half a banana with half an avacado.You can also try baby rice with some added puréed fruits.
7/8 months:
Fibrous cereals such as porridge or fortified cereals are a good staple and you add puréed fruits such as grapes, apple, kiwi, melon, strawberries, pear, banana, or whatever fruit your baby is partial to! Vitamin C rich foods such as oranges and kiwis are recommended with cereals as vitamin C helps aid iron absorption. You could also try scrambled eggs, toast or even a croissant.
12 months:
At around 12 months you can begin to add even more variety to your baby's breakfast. You can try some shredded wheat with milk, eggs (boiled, fried, scrambled), bacon, sausage, toast, croissant, fruit.
It is important to remember that soft boiled eggs and poached eggs are not suitable for babies under 12 months so should be avoided.
Fruit and yoghurt can also provide a good start to the day. When selecting yoghurt a lot of mums opt for natural yoghurt and add fruit purée for a healthier option. Avoid low fat yoghurts as they are not nutritionally suitable for babies. Don't give your baby sugar coated cereals as they aren't nutritious and this sweetness will only give them a sweet tooth which may result in long term problems with their teeth.You can also offer chopped fruit as a finger food for your baby’s breakfast.
For a treat, pancakes are a great idea once in a while.

More questions

Fibre is important in your baby's diet but should only be present in small amounts as it can prevent the absorbtion of important minerals.
Fat is a vital source of energy for your growing baby.
Gluten is contained in foods such as wheat, rye, barley, and oats which are alll good sources of iron and fibre.
Honey should never be given to a baby under 12 months due to the risk of botulism poisoning.
There are lots of wonderful first foods for your baby to try including puréed vegetables, fruit, and baby cereals. 
There are lots of great ways to easily prepare and cook food for your baby.
A good breakfast is vital to ensure your baby is getting the best start to the day. 
In the beginning you should only feed your baby a spoon or two of solid food a day. This will gradually build up over a period of a weeks until they are enjoying three meals a day.
It is essential that you provide your baby with a well balanced and nutritious diet. There is a wonderful variety of foods to choose from.
If you're having problems weaning your baby it may be that they just aren't ready. Take a week or two to resume milk feedings and try again.